Class A

Lib/test/test_coroutines.py:1196–1200

    def test_await_17(self):
        # See https://github.com/python/cpython/issues/131666 for details.
        class A:
            async def __anext__(self):
                raise StopAsyncIteration
            def __aiter__(self):
                return self

        with contextlib.closing(anext(A(), "a").__await__()) as anext_awaitable:
            self.assertRaises(TypeError, anext_awaitable.close, 1)